A rolling mill capable of forming a hot, continuously cast metallic strand into a strip, with a large bite and with one pass uses only two small diameter rolls, each mounted for rotation in a pair of chock blocks and each having a comparatively narrow, enlarged diameter working portion. The mill includes rotary brushes (142) that are adjustably loaded (152,154) against the working portions of the rolls to remove adhered strand material, and a release agent spray system to inhibit adhesion.
The Federal Aviation Administration has certain minimum standards with respect to the light shape and intensity provided by elevated airport runway, taxiway, and threshold edge lights. For example, for blue taxiway lights, FAA Advisory Circular AC 150/5345-48 in Fig. 6 provides for an isocandela curve for minimum output in blue light for the L-861-T Taxiway light.
Similar standards are provided by the Federal Aviation Administration for other colored and white lights. Comparable standardsexist in other countries dictated by the appropriate agency having jurisdiction in that particular country.
In order to meet these standards, the glass dome which surrounds the light source is formed with a varying internal shape which constitutes a prismatic lens so that the light may conform to these standards. It is essential that the relative relationship between the light source, which is an incandescent electric bulb, and the prismatic lens be maintained within very close tolerances. Variations of as little as 0.025 inches can result in the spectral shape not conforming to the minimum FAA or other country's requirements.
Additionally, the elevated airport runway, taxiway and threshold edge lights must be capable of being positioned absolutely level even though the vertical post on which they are supported may not be perfectly vertical as the result of installation procedures.
Furthermore, in climates where snow must be removed from the runway with snowplows, it is essential that the lights be identified with flags attached thereto which will extend above the snow so that the snowplow does not come in contact with the lights.
The present state of the art involves two type of elevated airport runway taxiway or threshold edge lights and are referred to as the twist lock tab-and the metal band- or metal clamp-type.
In the twist lock tab-type light the glass dome is provided with a segmented lip at the base thereof extending outwardly at right angles to the axis of the light in the form of three separate tabs. These tabs fit under comparable lips in the base of the light and the glass dome is secured by twisting it in a bayonet-type lock. The glass dome also abuts against an 0-ring positioned in a groove in the upper periphery of the base as a seal against water, ice and snow.
The disadvantages if this type of light are as follows: In the glass molding process, the thickness of the tabs at the base of the glass dome can vary as much as 1/16th of an inch in thickness. Thus when the glass dome is positioned in its bayonet joint the relative position of the prism in the glass dome with respect to the light source can vary to such an extent that the spectral shape of the light is altered so as not to meet minimum agency standards. Furthermore, the rotating motion of the glass against metal in seating the glass dome, either during initial installation or when replacing the light source, inherently has the possibility of chipping or cracking the dome and this is accentuated if ice or snow is present.
This type of light also, because of its construction, tends to channel any moisture into the area where the glass dome attaches to the metal base so that if there is any possible entrance point for moisture, the design encourages moisture to enter at such point.
The elevated airport runway, taxiway and threshold edge lights of this twist lock tab-type also are leveled by means of four separate leveling screws which require multiple adjustments and consequent excessive labor charges to achieve a level position of the light. Furthermore, the flag holder is so shallow that when the flag shaft is inserted therein, unless the shaft is wired or otherwise tied to the supporting conduit beneath the light, the flag will not remain in an upright position.
The metal band- or metal clamp-type elevated airport runway, taxiway or threshold edge light has all of the disadvantageous features described above with respect to the twist lock tab-type light.
In the metal band- or metal clamp-type light, the glass dome is positioned on the metal base by means of a circumferentially extending metal clamp or band which engages an outwardly extending lip on the metal base and a corresponding outwardly extending lip on the base of the glass dome. This type of junction inherently permits moisture to enter the interior of the glass dome and also variations in thickness of the glass lip which are normal in the glass manufacturing process will permit unacceptable positioning differences between the prism portion of the glass dome and the light source so as to cause the spectral shape of the light not to meet minimum standards. This type of light also has the same leveling and flag-holding disadvantages described above with respect to the twist lock tab-type light.
The present invention overcomes all of the above-described disadvantages of the prior art by providing an elevated airport runway, taxiway or threshold edge light with a glass dome which is effectively sealed against rain, snow, sleet, dust, or other unfavorable weather conditions.
It is a further object of this invention to provide such a light which mechanically prevents such weather elements from otherwise entering the interior of the light dome.
It is a still further object of this invention to provide such a light whereby the glass dome is always positioned precisely with respect to the light source regardless of variations in the shape of the glass dome as a result of the manufacturing process.
It is a still further object of this invention to provide such a light wherein the elevation and azimuth positioning of the light may be accomplished quickly and easily in the field.
It is a still further object of this invention to provide such a light in which the cover may easily, rapidly and safely be removed from the base in order to replace the light source and in which the cover may be replaced as easily, rapidly, and safely.
In accordance with this invention there is provided an elevated light comprising a substantially hollow base having a bottom wall, a ball joint centrally positioned in the bottom wall of said base and adapted to receive an upstanding conduit, said ball joint comprising adjustable securing means for fixedly positioning the base and ball joint assembly onto said upstanding conduit, means supported centrally on said base adapted to receive a light source, and a cover comprising a lower annular portion and a hollow glass dome including a prism portion sealed in said lower annular portion, said lower annular portion having an inner base portion resting on the upper portion of said hollow base, whereby the apex of said hollow glass dome is positioned a predetermined distance from said inner base portion and said bottom wall of the base, so that the prism portion is in proper registration with respect to the light source.
The lower annular portion of the cover has a downwardly extending peripheral portion which substantially overhangs said hollow base, thus providing an absolute seal against moisture or water entering the interior of the light. This construction also permits the glass dome to be positioned accurately within the cover in the resin support during the manufacturing process so that variations in thickness of the base of the glass dome or the size of the glass dome may be compensated for by its positioning in the resin , thus insuring that the prism portion of the glass dome is precisely aligned with 3 respect to the light source when the cover supporting the glass dome is attached to the base of the light, either during initial installation or when replacing the light source.
The adjustable securing means comprises a member posi- tionned below and engaging the ball joint, the member being removably secured to the bottom wall of said base, whereby the ball joint is secured to the upstanding conduit as it is secured to the bottom wall of said base, so as to facilitate elevation and azimuth positioning of the light base which may then be secured by three screws. Furthermore, since the edge of the cover extends downwardly over the light base, there is sufficient vertical space on the light base so as to provide a guide for exact positioning of the cover on the base which guide also functions as a flag holder having sufficient depth to hold the flagpole for snow removal purposes in a vertical position without the necessity of attaching the base of the flagpole to the conduit by wire or other means.
These, together with other objectives and advantages of the invention, should become apparent in the details of construction and operation, as more fully described herein and claimed, reference being had to the accompanying drawings forming a part hereof wherein like numerals refer to like parts throughout. In these drawings:
Referring first to Fig. 1, the light comprises a cover comprising a glass light dome 11 molded into and sealed in a lower annular portion 12 made from a polymeric resin which is preferably polyurethane. The lower annular portion 12 is positioned on a base and is secured against movement by a pair of threaded shafts 13 and wing nuts 14 provided with stops 15 or by an equivalent mechanism. The base is fixedly positioned onto an upstanding electrical conduit 16 which is shown positioned in a conventional vertical support 17 and the conduit 16 is held against movement by means of the screw 18. The member 19 is a part of the base which functions to align the cover and also functions as a flag holder adapted to hold the flagpole 20 of the snow flag 21.
Referring now more particularly to Fig. 2, it will be seen that the lower annular portion 12 of the cover is formed with an inner base portion 31 resting on the upper portion 32 of the substantially hollow base 26 having a bottom wall. It will be noted that the interior of the base 26 is protected from ingress of snow, rain, dust, etc. by means of the downwardly extending peripheral portion of the said lower annular portion 12 of the cover which substantially overhangs the hollow base 26, coupled with the fact that the glass dome 11 is sealed in the lower annular portion 12.
In the base 26 there is mounted centrally a socket 23 adapted to receive an incandescent light bulb 22 and connected in the usual manner to electrical leads 24. The light bulb 22 is located in the interior of the glass dome 11 which has an inner prism portion 25 that is precisely positioned in proper registration with respect to the light bulb 22. This is achieved in the manufacture of the instant invention by positioning the glass dome 11 in the lower annular portion 12, for instance in a jig, so that the apex of the hollow glass dome 11 will always be positioned a predetermined distance from said inner base portion 31 of the lower annular portion 12 and said bottom wall of the base 26 whereby the prism portion 25 of the glass dome 11 is in proper registration with respect to the light bulb 22.
The base 26, which is preferably made from a polyester resin or an equivalent material, is fixedly positioned onto the upstanding conduit 16 by means of the ball joint 27 together with adjustable securing means comprising the member 29 positioned below and engaging the ball joint 27 and it is removably secured to the bottom wall of the base 26 by means of the screws 28 of which there are three equispaced around the base 26 as may be seen more advantageously in Fig.3 which also shows the nuts 30 that hold the threaded shafts 13 in position. The ball joint 27 surrounds the upper end of the conduit 16 and is made of a compressible plastic material, for instance a polyester material, which also functions to act as a seal against moisture and dust. The base 26 is held in position on the ball joint 27 by the screws 28 being tightened which also act to secure the ball joint 27 to the upstanding conduit 16 as it is secured to the bottom wall of the base 26.
In installing this light in the field, the proper length of conduit 16 is chosen and the conduit 16 is secured in the holder 17 by means of screw 18. By loosening screws 28, the elevation and azimuth of the base 26 may be adjusted quickly and easily by virtue of the 360° of freedom in the horizontal plane provided by the ball joint 27 and then the screws 28 are tightened to hold the base 26 in that position and to seal the underside of the base from the entrance of moisture and dust. In installing the cover on the base 26, the member 19 provides positive position for the cover with respect to the base 26 and the cover is merely pushed down tightly on top of the base 26 and the wing nuts 14-14 are tightened and the installation is complete. Likewise, in removing the cover in order to change the bulb 22, it is a simple matter to loosen the wing nuts 14-14 and lift the cover vertically upward. Snow and ice cannot complicate this operation. In the event that it is necessary to use a snow flag 21, the flagpole 20 is merely inserted in the hole in the member 19 and thus is held in a vertical rigid position.
While this invention has been described in its preferred embodiment, it is appreciated that variations thereon may be made without departing from the scope and spirit of the invention.